Numerous fire-extinguishing devices and systems are known in the prior art for use in putting out a cooking fire, the most simple of which is a stand-alone conventional fire extinguisher. A significant drawback to the stand-alone extinguisher is that once it is located, it must be manually discharged. As a result, fire-extinguishing systems have been developed which include heat detecting means located above a stove top along with one or more fire-extinguishing material discharge heads. For example, U.S. Pat. No. 4,256,181 to Searcy, issued Mar. 17, 1981 discloses a fire-extinguishing system that is automatically actuated in response to flames from a fire on the upper surface of a stove having a vent hood. The system utilizes a fusible link, such as a nylon cord, coupled to a link which is secured to the fire-extinguishing valve. A plastic container of flammable material, such as gun powder, surrounds the fusible link and is connected to a fuse which extends below the vent hood. When flames from a fire ignite the fuse, the flammable material within the container is ignited, thereby severing the fusible link and opening up the fire extinguisher valve. There are several disadvantages to Searcy, most notably the use of a flammable material to actuate the fire extinguisher could create a greater danger under certain circumstances. In addition, Searcy does not provide any means for automatically terminating the power to the stove top.
U.S. Pat. No. 6,105,677 to Stager, issued Aug. 22, 2000, discloses the use of one or more fire-extinguishing canisters which are fixedly or pivotally mounted to the vent hood above a stove top, each canister being provided with an opening which is positioned to face downwardly toward the stove top. Each opening is covered by a cap through which a rod surrounded by an elongated compression spring is disposed and retained therein by a fusible plug soldered thereto. The fusible plug is composed of a material which melts upon reaching a predetermined temperature. When a fire occurs, the fusible plug instantly melts, the spring ejects the cap downwardly off the opening and fire-suppressing material contained within the canister is allowed to flow downwardly onto the fire. One drawback to Stager is the cumbersome cap cover/rod/compression spring arrangement. In addition, Stager does not provide means to automatically terminate power to the stove top.
Fire-extinguishing systems which both suppress a stove top fire and shut off the power supply to the stove top also are known in the prior art. For instance, U.S. Pat. No. 6,029,751 to Ford et al., issued Feb. 29, 2000, discloses a fire suppression system which is installed above a stove top comprising a pressurized cylinder containing nitrogen or an inert gas which is connected by piping through a pressure switch to a snap action, temperature activated valve. The temperature activated valve is opened by expansion of a temperature sensitive material, such as a metallic alloy element, within the valve body. Thus, when a fire occurs, the temperature sensitive material expands, the valve opens, and the fire suppressant material is discharged. The system is connected to electronic circuitry that utilizes a radio transmitter and receiver to activate a remote energy removal unit to disconnects the gas or electricity from the stove top. In U.S. Pat. No. 5,871,057 to Stehling et al., issued Feb. 16, 1999, a fire-extinguishing system is disclosed which suppresses a cook top fire with a fire suppressant dispensed through a battery charged nozzle, the batteries also providing current to an acoustic assembly which sounds an alarm and emits a signal to a receiver which shuts off current to the stove top.
U.S. Pat. No. 6,341,655 to Busian et al., discloses an emergency shutdown system for kitchen appliance fires, such as cook stoves. The shutdown system comprises a detection system for detecting a fire in the form of a cable having heat fusible links, a fire extinguisher which is connected by a conduit to discharge valves positioned above the burners of a cook top and a control system having an audible alarm and a visual alarm in the form of a strobe light and connection means to the gas or electric energy source. The system automatically is actuated upon sensing a fire, activating the fire extinguisher, the means for shutting off the stove, and the alarms for indicating the emergency condition.
Other patents which disclose cook stove fire extinguisher installations that comprise means for automatically activating the fire extinguishers and for shutting off the stoves when the fire extinguishers are activated include U.S. Pat. No. 4,813,487 to Mikulec et al., issued Mar. 21, 1989, U.S. Pat. No. 4,830,116 to Walden et al., issued May 16, 1989, U.S. Pat. No. 4,979,572 to Mikulec, issued Dec. 25, 1990, U.S. Pat. No. 5,063,998 to Quinn, issued Nov. 12, 1991 and U.S. Pat. No. 5,297,636 to North, issued Mar. 29, 1994.
Despite the advances of the prior art, a need still exists for a fire-extinguishing system that is adapted both to automatically extinguish a stove top fire and that can be adapted to terminate power automatically to the stove top. Such a fire extinguisher system should include a fire-extinguishing device that is installed quickly and easily above a stove top. Such a fire-extinguishing device should be provided with a discharge head that can be replaced without uninstalling the device. In addition, such a fire-extinguishing device should be capable of having multiple discharge heads. Further, such a fire-extinguishing system should be capable of terminating the power to either a gas or electric stove by simple electrical circuitry without the use of a transmitter/receiver signal. Moreover, such a fire-extinguishing system should be include a mechanism integrated with the fire-extinguishing device to terminate power to a stove top. Such a fire-extinguishing system also should be provided with an audible and/or visual warning alarm. Such a fire-extinguishing system should be inexpensive to manufacture and affordable for purchase by a consumer